since the snapshot 22w43a, trying to connect to a server with online-mode=false will result on the following message "Invalid signature for profile public key".

This message doesn't show in previous snapshots or versions and doesn't show either when online-mode=true.

this problem may be caused because of one of those two changes in 22w43a: "Servers can now lazily distribute players profile public keys along with their first chat packet" or "Profile public keys will now be refreshed without reconnecting"